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Configure TWAMP

The Two-Way Active Measurement Protocol (TWAMP) defines a standard for measuring IP performance between two devices in a network. For more information on TWAMP, see RFC 5357, A Two-Way Active Measurement Protocol (TWAMP). For more background information on TWAMP, see Understand Two-Way Active Measurement Protocol.

Understand TWAMP Configuration

Two-Way Active Measurement Protocol (TWAMP) support and configuration varies for hardware platform, physical interfaces, or virtual physical (services) interfaces. Support for RPM is not always an indicator of TWAMP support on a particular combination of platform and line card for Junos OS. The time stamps used in RPM and TWAMP are added in different places, depending on the hardware configuration. For example, different hardware components perform timestamping, either inline in the lookup (LU) chip, Routing Engine (Junos OS Evolved), the microkernel-based timestamping at the host Packet Forwarding Engine, or the line card such as a Multiservices Physical Interface Card (MS-PIC), Multiservices Modular Interface Card (MS-MIC), Multiservices Modular PIC Concentrator (MS-MPC), or Multiservices Dense Port Concentrator (MS-DPC).

Use Feature Explorer: Two-Way Active Measurement Protocol to confirm platform and release support for specific features.

See Understand Two-Way Active Measurement Protocol for Junos OS Evolved differences and notes about your platform.

TWAMP Light Support

TWAMP Light, as defined in Appendix I of RFC 5357, is a stateless version of TWAMP where test parameters are predefined instead of negotiated. All test packets received by the server on a test port are reflected back and forgotten right away.

Support for IPv6 target addresses for TWAMP Light test sessions is introduced in Junos OS Release 21.3R1. For the Junos OS IPv6 TWAMP Light client, you must configure both the target-address and the destination-port statements at the [edit services rpm twamp client control-connection control-client-name test-session test-session-name] hierarchy level. Support for link-local target addresses for IPv6 TWAMP Light test sessions is introduced starting in Junos OS Release 21.4R1 and in Junos OS Evolved Release 22.3R1, for those devices that support TWAMP Light.

Simple Two-Way Active Measurement Protocol (STAMP) Support

STAMP, as defined in RFC 8762, Simple Two-Way Active Measurement Protocol (STAMP), standardizes and expands upon the TWAMP Light operational mode, which was defined in Appendix I of RFC 5357, Two-Way Active Measurement Protocol (TWAMP). A STAMP-compliant reflector ensures symmetric payload size (in accordance with RFC 6038) and operates in either stateless or stateful mode, depending on whether the sequence number in the reflected payload is copied from the client frame or generated independently. A stateful reflector can detect in which direction drops have occurred. In previous releases, we supported symmetric payloads and stateless reflection. We now support stateful reflection, full compliance with the STAMP standard, and unidirectional drop values for clients. We support unidirectional drop values not only for STAMP clients, but also for TWAMP-Managed-mode clients. For Junos OS Evolved, STAMP is configured at the [edit services monitoring twamp server light] hierarchy level. Stateful reflection is configured with the stateful-sequence statement. For servers, the new default for offload-type is now pfe-timestamp instead of inline-timestamp.

Use Feature Explorer: Simple Two-Way Active Measurement Protocol (STAMP) to confirm platform and release support.

TWAMP Managed Support

For Junos OS, TWAMP is configured at the [edit services rpm twamp] hierarchy level. For Junos OS Evolved, TWAMP is configured at the [edit services monitoring twamp] hierarchy level.

Use Two-Way Active Measurement Protocol to confirm platform and release support for specific features.

Configure a TWAMP Server

With the exception of physical interfaces, TWAMP server configuration for Junos OS requires the following minimum configuration at the [edit services rpm twamp] hierarchy level:

Starting in Junos OS Release 21.3R1, you no longer need to configure the authentication-mode statement. The default mode is now none, which means that communications with the server are not authenticated.

  • To specify the list of allowed control client hosts that can connect to this server, include the client-list statement at the [edit services rpm twamp server] hierarchy level. Each value you include must be a Classless Interdomain Routing (CIDR) address (IP address plus mask) that represents a network of allowed hosts. You can include multiple client lists, each of which can contain a maximum of 64 entries. You must configure at least one client address to enable TWAMP.

  • ACX Series routers do not support authentication and encryption modes. The value for authentication-mode statement at the [edit services rpm twamp server] hierarchy level must be set to none.

  • TWAMP control connection traffic always arrives on ACX routers with the listening port set as 862. Because this port number for traffic probes can be modified, probes that arrive with a different port number are not recognized and processed by ACX routers correctly. As a result, TWAMP traffic and host-bound packets are dropped in such a scenario.

Configure TWAMP provides information about support for light control of the server.

For Junos OS, you can configure light control for the server (managed control is the default). The Junos OS TWAMP server configuration for light control requires the following minimum configuration at the [edit services rpm twamp] hierarchy level:

For Junos OS, for a list of restrictions on source addresses, see source-address (TWAMP).

For Junos OS Evolved, you can configure either managed or light control for the server. TWAMP server configuration for managed or light control requires the following minimum configuration at the [edit services monitoring twamp] hierarchy level, assuming you use the default port for TWAMP (862):

For Junos OS Evolved, you cannot use the following addresses for the client-list source IP address used for probes:

  • 0.0.0.0

  • 127.0.0.0/8 (loopback)

  • 224.0.0.0/4 (multicast)

  • 255.255.255.255 (broadcast)

You can configure more than one client, and you can change the TWAMP listening port as long as the change is coordinated with the TWAMP client.

For microkernel-based timestamping in Junos OS, you don’t need to configure an si- interface. In this case, the TWAMP connection and sessions are established based on the target address and route.

For inline timestamping in Junos OS, you need to configure si- or sp- services interfaces and theTWAMP server configuration requires the following statements at the [edit interfaces service-interface-name] hierarchy level:

Note:

You cannot configure the TWAMP server on unit 0 of a services interface. If you try, you will receive a configuration error.

(Junos OS only) To configure a TWAMP server on an inline services (si-) interface, configure the amount of bandwidth reserved on each Packet Forwarding Engine for tunnel traffic using inline services by including the bandwidth (1g | 10g) statement at the [edit chassis fpc slot-number pic number inline-services] hierarchy level. Specify the service PIC (sp-) logical interface that provides the TWAMP service by including the twamp-server statement at the [edit interfaces sp-fpc/pic/port unit logical-unit-number family inet] hierarchy level.

The twamp-server statement is not required for physical interface TWAMP server configuration.

Many other TWAMP server parameters are optional. See the TWAMP server configuration statements for details.

Configure a TWAMP Client

For Junos OS, to configure the TWAMP client service, include the client statement and related parameters at the [edit services rpm twamp] hierarchy level. For Junos OS Evolved, include the client statement and related options at the [edit services monitoring twamp] hierarchy level.

There are many options available for TWAMP client configuration. See the configuration statement topics and examples for details.

For microkernel-based timestamping in Junos OS, you don’t need to configure an si- interface. In this case, the TWAMP connection and sessions are established based on the target address and route.

For inline timestamping in Junos OS, the si- interfaces are virtual physical interfaces that respond as a TWAMP server. However, you can also configure services interfaces to act as the TWAMP client, which performs the TWAMP controller role.

(Junos OS only) To configure a services interface as a TWAMP client, you configure the service parameters and the service interface as a TWAMP client.

To configure the TWAMP client services interface, include the rpm twamp-client statement at the [edit interfaces si-interface-name] hierarchy level:

Note:

You cannot configure the TWAMP client on unit 0 of a service interface. If you try, you will receive a configuration error.

See Also

Change History Table

Feature support is determined by the platform and release you are using. Use Feature Explorer to determine if a feature is supported on your platform.

Release
Description
23.4R1-EVO
Starting in Junos OS Evolved Release 23.4R1, we support RFC 8762, Simple Two-Way Active Measurement Protocol (STAMP). RFC 8762 standardizes and expands upon the TWAMP Light operational mode, which was defined in Appendix I of RFC 5357, Two-Way Active Measurement Protocol (TWAMP). A STAMP-compliant reflector ensures symmetric payload size (in accordance with RFC 6038) and operates in either stateless or stateful mode, depending on whether the sequence number in the reflected payload is copied from the client frame or generated independently. A stateful reflector can detect in which direction drops have occurred. In previous releases, we supported symmetric payloads and stateless reflection. With this release, we support stateful reflection, full compliance with the STAMP standard, and unidirectional drop values for clients. We support unidirectional drop values not only for STAMP clients, but also for TWAMP-Managed-mode clients. For servers, the default for the offload-type statement is now pfe-timestamp instead of inline-timestamp.
22.4R1-EVO
Starting in Junos OS Evolved Release 22.4R1, we support IPv6 source and target addresses (except for link-local addresses) for client lists, control connections, and test sessions.
22.4R1-EVO
Starting in Junos OS Evolved Release 22.4R1, you can configure SNMP traps for TWAMP.
22.4R1-EVO
Starting in Junos OS Evolved Release 22.4R1, we support inline timestamping, where the timestamping is done in hardware at the generator or the reflector.
22.3R1-EVO
Starting in Junos OS Evolved Release 22.3R1, for TWAMP Light test sessions, you can specify IPv6 link-local addresses for target addresses.
21.4R1-EVO
Starting in Junos OS Evolved Release 21.4R1, IPv6 source and target addresses (except for link-local addresses) are supported for client lists, control connections, and test sessions.
21.4R1
Starting in Junos OS Release 21.4R1, for TWAMP Light test sessions, you can specify IPv6 link-local addresses for target addresses, and can configure IPv6 addresses for source addresses that correspond to target addresses configured with IPv6 link-local addresses.
21.3R1
Starting in Junos OS Release 21.3R1, IPv6 target addresses for TWAMP Light test sessions are supported.
21.3R1
Starting in Junos OS Release 21.3R1, you no longer have to configure the authentication-mode statement for the TWAMP server. The default mode is none.
21.1R1
Starting in Junos OS Release 21.1R1, we support the Two-Way Active Measurement Protocol (TWAMP) Light client and server, as defined in Appendix I of RFC 5357, for IPv4 target addresses. TWAMP Light is a stateless version of TWAMP, where test parameters are predefined instead of negotiated. All test packets received by the server on a test port are reflected back and forgotten right away.